Fracture Investigation of the Ductile Materials Using Phase-Field Model
- Peyman Esmailzadeh,
- Mohsen Agha Mohammad Pour,
- Reza Abdi Behnagh,
- Dong Lin
Abstract
Phase-field models have been the subject of a great deal of research in
recent years. Investigations have revealed that the phase-field model is
capable of generating complex crack patterns. This is gained by
replacing the sharp discontinuities with a scalar phase damage field
comprising the diffuse crack topology. In the previous models, cracks
are blurred into the surrounding areas due to introducing dependency of
degradation function to a single parameter, strain threshold. The stable
crack initiation and propagation require estimation of complex
higher-order degradation function, which should be solved either by a
new iteration scheme or using extremely small loading increment.
However, this demands considerably high computational cost. In this
study, the nonlinear coupled system comprising the linear momentum
equation and the diffusion-type equation governing the phase-field
evolution is solved concurrently through a Newton--Raphson approach.
Moreover, an improved degradation function and staggered iteration
scheme are solved by a one-step paradigm is proposed. Such that the
computational costs can be reduced, and the stability of crack
propagation can be improved. A phase-field model for ductile fracture is
carried out in the commercial finite element software Abaqus by means of
UEL and UMAT subroutines. Post-processing of simulation results is
implemented through an added subroutine implemented in the visualization
module. Several benchmark problems show the proposed model's ability to
reproduce some essential phenomenological characteristics of ductile
fracture as documented in the experimental literature.